Diesel fuel system



y 1967 P. w. STANKOVICH 3,322,068

DIESEL FUEL SYSTEM Filed Dec. 30, 1965 INVENTOR.

v w k M 4T7'OR/VEYS United States Patent Ofi ice 3,322,068 Patented May 30, 1967 3,322,068 DIESEL FUEL SYSTEM Paul W. Stankovich, Romeo, Mich., assignor to Holley Carburetor Company, Warren, Mich., a corporation of Michigan Filed Dec. 30, 1965, Ser. No. 517,627 4 Claims. (Cl. 103-2) This invention relates generally to diesel engines, and more particularly to an improvement in fuel injection systems therefor.

Diesel engines-have been in use for a considerable number of years, and many multi-cylinder diesel engines are supplied with fuel by an engine driven fuel injection pump having an in-line arrangement of injectors which are retained in the pump housing by what are commonly referred to as injection pump delivery valve retainers. The retainers are threaded into openings at' the top of the housing, and the fuel lines to the individual engine cylinders are connected by threaded fittings to the protruding free ends of these valve retainers.

After initial assembly of the fuel pump and fuel lines on the engine, it is frequently necessary to disconnect and reconnect the fuel lines, as in the case of maintenance in the field. In the initial assembly of the fuel pump, the retainers are threaded and tightened into the housing under a specified torque, which is very important because the injectors involve high pressure sealing surfaces and tight clearance, lapped parts. Thus, it is necessary to provide sufiicient torque or holding force to effect the seals, but not to exceed the required torque so as not to distort or otherwise damage the tight fitting pump parts.

In other words, suflicient torque must be used in tightening down the retainers to seal the high pressure fuel against leakage, which is obviously generally o-bjectiona-ble and which may even adversely effect engine operation if the leakage is excessive. On the other hand, the specified torque must not be exceeded; otherwise, expensive pump parts might be damaged.

The retainers are torqued down at the factory with a torque wrench. However, a torque wrench'may not be available in the field. Obviously, where no such means for preventing turning of the retainers in the housing are provided, and this is sometimes the case, mechanics either tend to forget or are too inexperienced to use wrenches to prevent a retainer from turning in the-housing when fuel lines are being removed orattached, or else the pump design is such that the retainers are too close together to permit the use of wrenches. Therefore, it is highly desirable that these critical torque settings be retained during simple service operationsin the field which may require disconnecting the fuel lines. In other words, torque developed in loosening or tightening the fuel line fittings on the threaded free ends of the retainers should be somehow isolated or prevented from loosening or further tightening the retainers in the housing.

A number of devices have been employed in the past for this purpose. However, despite the fact that diesel engines have been used for many years, none of these devices provide a really satisfactory solution for this problem. For example, the retainers are often provided with an intermediated portion having a hexagonal configuration to accommodate a wrench, and one method employed in the past for preventing the loosening or tightening thereof in the housing is to provide a heavy bar having openings therein, the bar being fitted over the row of retainers and somehow secured in place, as by bolts. While this accomplishes the desired result, the bar and bolts are too expensive for the function they perform.

Another method that is employed, particularly where the retainers are formed near the portion thereof adjacent the housing with a serrated outer surface, is to place semi-spherical blocks on opposite sides of adjacent pairs of retainers and draw the two blocks together by bolts. This, again, involves a number of parts for each pump, complicates the configuration with numerous crevices and protrusions that tend to collect dirt and hard to clean and often does not provide the holding power required when the conduit connector threads are dry or rusty.

Still another method is to provide a strap having a hexagonal opening receiving the hexagonal portion of the retainer, the other end of the strap being bolted to the housing by a separate bolt. This again, complicates the pump configuration and adds to the cost and the difficulty of assembling and cleaning the pump.

It s true that in using any of the above mentioned do vices, the retainers are protected against turning to some extent when the fuel line fittings are tightened or loosened. However, the protection is not complete and these devices have the aforementioned disadvantages.

In pumps having sealed banjo or side outlet type. fuel line fittings, the banjo fittings are provided with a seal on each side thereof. Straps between adjacent pairs of retainers have been employed, the straps being tightened against the upper seal of each fitting by a cap nut. However, these straps do not perform the function of preventing tightening or loosening of the retainer in the housing when the cap nut is tightened or loosened, even though the other end of the strap on the adjacent retainer is tightened down. As soon as the cap nut is loosened to take the pressure off the strap on one retainer, that particular retainer can turn in the housing if the torque required to loosen or tighten the cap nut exceeds the torque required to tighten or loosen the retainer, as where the cap nut threads may be rusted or corroded or have, for one reason or another, a very tight fit or frictional drag. That is, once the strap on the retainer in question is loosened, the fact that the other end of the strap is tight on the adjacent retainer does not solve the problem because the cap nut may turn the retainer on which it is threaded. Side outlet fittings create a greater problem because they must be properly aligned angularly to provide room therebetween for attachment of the fuel lines.

Accordingly, a general object of the invention is to provide a simple, inexpensive and efiicient means for assuring that diesel pump delivery valve retainers will maintain a particular torque setting during installation, operation, and removal of the engine fuel injection pump.

Another object of the invention is to provide such a means which utilizes one valve retainer to assist retaining an adjacent valve retainer in place during the installation or removal of the fuel line from the adjacent valve retainer, as when the pump is being assembled on or removed from the engine.

A more specific object of the invention is to provide such-a means which comprises a strap and jam nut assembly connecting a pair of adjacent valve retainers.

A still further object of the invention is to provide such an assembly which need not be loosened unless it is desired to remove the valve retainers from the pump housing; that is, the assembly is not required to be loosened when the fuel lines are being attached or removed.

Other objects and advantages of the invention will become more apparent when reference is made to the follow- FIGURE 2 is a partial, vertical cross-sectional view taken through a portion of FIGURE 1;

FIGURE 3 is a cross-sectional view taken along the plane of line 33 of FIGURE 2 and looking in the direction of the arrows.

Referring now to the drawings in greater detail, FIG- UrRE 1 is a simplified schematic illustration of a diesel engine 10, including the usual fuel injection pump 12, having any number of cylinders 13. The pump 12 receives fuel from a suitable source 14 via any suitable condu-itry system 15 and includes a delivery valve assembly 16 for each of the cylinders 13. A fuel conduit 18 is connected between each of the valve assemblies 16 and one of the nozzles 20, which inject the fuel into its respective engine cylinder 13.

7 As illustrated in FIGURE 2, the delivery valve assembly 16 includes a valve retainer 22 having three sets of external threads 24, 26 and 28, the threads 24 being screwed into a threaded opening v30 formed in the pump 12. The assembly 16 further includes the usual internal valve components, such as elements 32, 34, 36 and 38, which serve to control the flow of fuel through the retainer 22. These elements form no part of the invention; thus, they wil not be further discussed. A cap nut 40 connects the conduit 18 to the threaded outlet end 28, the tube 18 having a ball or other suitable end 42 formed thereon which seats on a tapered opening 44 at the top of the retainer 22.

A collar 46, which is usually hexagonally shaped to accommodate a wrench, is formed on the outer surface of the retainer 22 at some intermediate location thereon, an externally threaded portion 26 being formed adjacent the upper face 48 of the collar 46. A relatively thin metal strap 50 positioned adjacent the upper face 48 includes a pair of openings 52 (FIGURE 3) formed therein, the distance between the openings determined by the distance between the centerlines of adjacent valve retainers 22 so that the strap can be placed over a pair thereof. The strap 50 is held against the face 48 by a jam nut 54 for a purpose which will be described later.

In order to better understand the invention, a discussion of the assembly operation is in order. First, a valve retainer 22, including the internal valving elements 32, 34, 36 and 38, would be threaded into each of the openings 30 of the pump housing 12. It would thereupon be tightened or torqued down to some predetermined setting in order to assure a high pressure seal joint. Next, the strap 50 would be placed over two adjacent retainers 22 and clamped in place on the upper faces 48 of the flanges 46 by means of a pair of jam nuts 54, the jammed down straps serving to lock the adjacent retainers. Lastly, the tubes 18 are connected to the upper ends of the retainers 22 by means of the connectors 40 being threadedly attached to the end 28, causing the ball end 42 of the conduit 18 to be pressed tightly against the tapered seat 44.

Another reason why the torque specification for the retainers 22 is important is that where the retainers are steel and the housing 12 is aluminum, excess torque in setting the retainers could damage internal parts of the housing. Also, as the straps 50 are not employed, the specified torque on the retainers 22 is greater than that for the connectors 40 so that the latter can be loosened.

As already stated, it is frequently necessary, as in the case of simple maintenance in the field, to remove the fuel lines 18 without loosening the retainers 22, the latter being due perhaps to the fact that the torque wrench is not available. When the straps 50 are employed, tests have proven that, once the jam nuts 54 are properly torqued down against the straps 50 any tightening or loosening of the tube connectors 40 on the outlet end 28 of the valve retainer 22 requiring as much as over twice the torque setting at the pump end 24 will not tighten or loosen either retainers .22 in the pump housing 12. In the contrast to this, without the strap 50 and jam nut 54, any tightening or loosening of the tube connector 40 under a torque greater than that at which retainer 22 is set is apt to disturb the torque setting of the retainer 22, which may result in fuel leakage occurring past the threads 24. It should also be apparent that during operation of the pump 12 and engine 10, particular valve retainers 22 might tend to become loosened under constant vibration, and such loosening is prevented by the incorporation of the invention.

It should be further apparent that the addition of the strap and jam nut arrangement represents an extremely simple, inexpensive and yet highly reliable means for assuring the retention of the required torque relationship between the valve retainers and the pump housing. Such an arrangement also eliminates having to space adjacent valve retainers far enough apart to provide wrench clearance therebetween and, hence, results in a more compact design and does not depend upon an operators memory.

While but one embodiment of the invention has been shown and described, it is apparent that other modifications of the invention are possible, and no limitations are intended except as recited in the appended claims.

What I claim as my invention is:

1. A fuel injection system for a multi-cylinder diesel engine, comprising a fuel injection pump housing containing a plurality of fuel delivery means, a threaded opening in the wall of said housing adjacent each of said means, a delivery means retainer having a fuel passage therethrough screwed into each of said openings under a predetermined torque, the portion of each of said retainers extending from said housing having a shoulder extending radially therefrom, a strap having an opening at each end thereof positioned on each adjacent pair of said retainers, one of said retainers being received in each of said end openings, means co-operating with each of said pair of retainers to clamp said strap against said shoulder, a fuel conduit for each of said retainers for delivering fuel therefrom to one cylinder of said engine and means operable by rotation thereof co-operating with the free end of each of said retainers for sealing said conduits against fuel leakage, each of said straps serving toretain said adjacent pair of retainers in their originally torqued condition when said last named means are tightened or loosened under a torque greater than that required to turn said retainers in said housing.

2. A system such as that recited in claim 1, wherein the portion of each of said retainers extending from said housing has external threads adjacent said shoulder and said second named means comprises a jam nut tightened on said external threads to clamp said strap against said shoulder. I

3. A system such as that recited in claim 1, wherein external threads are formed near the free ends of said retainers and said third named means comprises an internally threaded member co-operating with said external threads.

4 A fuel injection system for a multi-cylinder diesel engme, comprising a fuel injection pump housing containmg a plurality of fuel delivery valves, a threaded opening in the wall of said housing adjacent each of said valves, a retainer having a fuel passage therethrough screwed into each of said openings under a predetermined torque, the portion of each of said retainers extending from said housing having external threads between the free end thereof and a shoulder extending radially therefrom, a strap having an opening at each end thereof positioned on each adjacent pair of said retainers, one of said retainers being received in each of said end openings, a jam nut tightened on each of said pair of retainers so as to clamp strap between said shoulder and said jam nut, a fuel conduit for each of said retainers for delivering fuel from each of said valves to one cylinder of said engine and a threaded connector co-operating with the free end of each of said retainers for sealing said conduits against fuel leakage, each of said straps serving to retain said ad acent pair of retainers in their originally torqued con- 5 6 dition when said connectors are tightened or loosened 1,973,658 9/1934 Redding 28580 under a torque greater than that Which would turn said 2,641,238 6/1953 Roosa 103-2 retainers in said housing. 2,694,977 11/1954 Rotter 1032 3,004,777 10/1961 Buonaccorsi 285-137 References 5 3,195,561 7/1965 Sovitzky 285 -61 UNITED STATES PATENTS DONLEY I. STOCKING, Primary Examiner.

1,473,751 1 1/1923 Walker 285-80 1,590,032 6/1926 Jauch 292-307 .2 W. J. KRAUSS, Assistant Examiner. 

1. A FUEL INJECTION SYSTEM FOR A MULTI-CYLINDER DIESEL ENGINE, COMPRISING A FUEL INJECTION PUMP HOUSING CONTAINING A PLURALITY OF FUEL DELIVERY MEANS, A THREADED OPENING IN THE WALL OF SAID HOUSING ADJACENT EACH OF SAID MEANS, A DELIVERY MEANS RETAINER HAVING A FUEL PASSAGE THERETHROUGH SCREWED INTO EACH OF SAID OPENINGS UNDER A PREDETERMINED TORQUE, THE PORTION OF EACH OF SAID RETAINERS EXTENDING FROM SAID HOUSING HAVING A SHOULDER EXTENDING RADIALLY THEREFROM, A STRAP HAVING A SHOULDER AT EACH END THEREOF POSITIONED ON EACH ADJACENT PAIR OF SAID RETAINERS, ONE OF SAID RETAINERS BEING RECEIVED IN EACH OF SAID END OPENINGS, MEANS CO-OPERATING WITH EACH OF SAID PAIR OF RETAINERS TO CLAMP SAID STRAP AGAINST SAID SHOULDER, A FUEL CONDUIT FOR EACH OF SAID RETAINERS FOR DELIVERING FUEL THEREFROM TO ONE CYLINDER OF SAID ENGINE AND MEANS OPERABLE BY ROTATION THEREOF CO-OPERATING WITH THE FREE END OF EACH OF SAID RETAINERS FOR SEALING SAID CONDUITS AGAINST FUEL LEAKAGE, EACH OF SAID STRAPS SERVING TO RETAIN SAID ADJACENT PAIR OF RETAINERS IN THEIR ORIGINALLY TORQUED CONDITION WHEN SAID LAST NAMED MEANS ARE TIGHTENED OR LOOSENED UNDER A TORQUE GREATER THAN THAT REQUIRED TO TURN SAID RETAINERS IN SAID HOUSING. 